rohlemann



June 2, 1931. H. RUHLEMANN 1,807,703

PROCESS OF AND MEANS FOR TIMING ELECTRIC FUSES Filed Dec. 16. 1 29 2 Sheets-Sheet 1 ,ATrn RN EV June 2, 1931. I-IIIRUHLEMANN 1,807,708

PROCESS OF AND MEANS FOR TIMING ELECTRIC FUSES File Dec- 16, 1 29 '2 Sheets-Sheet 2 Ve R2 INVENTEIFQ fie r erz jfljem rm RN E.\/. Q

Patented June 2, 1931 HERBERT R'O'HLEMZAITN, OF SOMMEBDA,

GERMANY, ASSIGNOR T RHEINISCHE METALLWAAREN-UND MASCHINENFABRIK, OF DUSSELDORF-DERENDORF, GEE- MANY, A CORPORATION OF GERMANY PROCESS-OI AND MEANS FOR TIMING ELECTRIC FUSES Application filed December 16, 1929, Serial No. 414,499, and in Germany June 14, 1929..

This invention relates to a process of and means'fortiming electric fuses having two oppositely connected condensers to furnish the ignition current.

It has already been proposed to vary the time of ignition of fuses of this type by varying the charging potential difference applied to the condensers, i. e., by using a difierent adjustment of the charging potential ,for each different time period desired.

The present invention accomplishes the same result by varying the charging potentials of the two condensers relatively to each other.

In accordance with this feature, the invention provides, in electrical time igniting devices, which comprise two condensers connected in opposition and provided with means for mutual variation of the voltage of their charging energy, for adjusting the different times 0 ignition by varyingsthe charging voltage of the two condensers relatively to one another. For this purpose there is added to l the above mentioned time ignition device hav-l '25 ing two condensers connected in opposition, a

source ofelectric current, said current source being capable of simultaneously delivering two difierent voltages which are variable with respect to one another and of feeding a respective one of said volt-ages to each of the condensers respectively to charge the' same.

In contradistinction to such prior methods, according to which both the condensers of such a fuse are indeed charged to different voltages to secure the difierent time periods,

but always uniformly in each case, i. e., bot being. charged to the same potential, the new process and device present the advantages that all the required time periods can be provided for with a relatively low potential difference. For'example,where the old process required for a very accurate ignition time period in the fuse for shells of about one second firing period, a charging potential difference of about 1000 volts, a maximum of only about 200 volts is suflicient with my invention, and this not only simplifies the battery or other source of current but also the structure and the insulation of the condensers 50 in general.

ference between To adapt the new process in practice, the charging apparatus for the two condensers is arranged to furnish two potential differences simultaneously, one at least of which is adjustable.

The new time ignition device and the methods of timing attainable thereby are described hereinafter in connection with the drawings.

.Figure l of the drawings shows the dlagram of connections of an electrical time ignitor together with the source ofcurrent belonging thereto; and

Figs. 2 to 4 are diagrams showing curves I between potential and time, i.-'e.', the relation between the discharges of the two condensers for difierent time periods; in Fig. 2, the

charging potential of the condenser which is shunted by a resistance is varied; in Fig. 3,

the charging potential of the other condenser 3 is varied; and in Fig. 4, the charging potentials of both condensers are varied simultaneously.

In the diagram, Fig. 1, A is'the fuse and B the charging apparatus. The two condensers e and f are connected in opposition to each other through a spark gap g, such as a tube containing a rare gas which allows the current to flow only at a potential of a predetermined minimum value, and an ignition medium h, The condenser f is also shunted by a constant high resistance.

The chargingapparatus B is provided with three terminals I0 I0 and it and furnishes a constant potential between 70 and k the potential between 70 and k is variable, relah tively to the constant potential of I0 and k within such maximum and minimum limits that the difference of potential between 70 and I0 and between 70 and k always lies below the potential difference necessary to break down the spark gap g.

The constant potential difference between J0 and k serves to charge one of the ignition while the variable potential difkg and k is applied to the condenser 7, which is shunted by the resistance i. In the time-potential diagram of Fig. 2, the line R represents the; discharge of the condenser c after it is charged to the concondensers e,

stant potential V. and after the disconnection of the condenser terminals from the source of current. The curves S S and S show the discharge rates of the second condenser 7 under the conditions produced by the varying charging potentials V V and V The diagram shows that the potential, necessary to break down the spark gap 9 (potential V and, therefore, to ignite the substance h, builds up between the condensers c and f after varying periods of time, t t and t and does so the more rapidly in proportion as the variable charging potential for condenser f is lower relatively to the constant potential for the other condenser 6.

Instead of varying the charging potential for condenser 7, which is shunted through resistance i, that for the other condenser 0 may be varied by a suitable arrangement of the connections between the charging apparatus and the fuse; the time-potential diagram of Fig. 3 represents these conditions.

In order to obtain a long time point 75 one of the condensers, as f, is charged by the potential V and the other condenser 0 with the potential V For shorter time periods t or the potential of condenser c is increased to V g or V The diagram shows that, in order to obtain very short time periods, the condenser e must be charged with a potential, which is approximately equal to the sum of the charging potential V, of the second condenser f plus the ignition potential V,;. This is, however, the highest potential to which the insulation of the fuse is subjected. 'The discharge curve S beginning at potential V of the condenser f is flatter in the course of a discharge, since the rate of discharge of the condenser constantly diminishes, and it follows that the accuracy of the adjustments for large time periods becomes lower.

The combined adjusting method, represented by way of example in the diagram of Fig. 4, obviates this disadvantage, by varying the charging potential of both condensers. The charging apparatus B, Fig. 1, is then arranged to furnish a variable potential both between the terminals and h and between the terminals 70 and k .Thetcondenser .f, Fig. 1, which discharges through the resistance z', is charged for a certain interval for short time periods with a potential Viz and for the remaining time periods with the potential V This higher potential V then furnishes a sufliciently rapid discharge for the longer time periods, so that asatisfactory accuracy of the actual ignition time period is obtained. The further adjustment within this restricted time period is then obtained by varying the charging potential of the second condenser e, so that the time period 2? is obtained with potential V and time period it, with potential V For the longer time periods 6 or t the condenser f, shunted by the resistance 5, is first charged with the greater potential V and then the further adjustment is obtained by varying the second chargin potential, so thatthe time period t results rom potential V and time period t, from potential V8 I claim as my invention 1. An electrical time ignition device com prising an electrical ignitingmeans, a spark gap, two condensers, a circuit connecting said condensers in oppositionto one another, and also including, in series therewith, the ignit ing means and the spark gap, a high resistance shunted across the terminals of one of said condensers, and a source of electricity capable of simultaneously delivering two different voltages, Variable with respect to one another, and connections whereby said voltages may be temporarily applied to the respective condensers to charge the same.

2. A method of adjusting the time of ignition of electric fuses which consists in charging two condensers to different voltages dependent upon the ignition time desired, maintaining one of the condensers at substantially itsfull charging voltage, partially discharging the other condenser at a rate determined by a constant resistance across its terminals, opposing the voltages of the two condensers to one another, and applying the progres sively increasing difierence of the said voltages to produce a discharge through a gap having a definite minimum break down voltage and through the fuse, in series with one another, causing said discharge to ignite the electric fuse at a definite time.

In testimony whereof, I aflix my signature.

HERBERT R'UHLEMANN. 

